PNAS allows authors to keep copyright

Beginning with papers submitted in January 2009, PNAS authors will retain copyright to their work and will give the National
Academy of Sciences an exclusive license to publish it. PNAS copyright policy has evolved over the years, and this change
is the next logical step in providing reasonable, flexible rights that balance the interests of authors, readers, and the
publisher.

Before 1993, authors held copyright to their papers and PNAS registered copyright only to the collective work. We encountered
some legal hurdles several years ago when we scanned and published online in JSTOR and PubMed Central articles for which we
did not own copyright.

From 1993 to 2008, PNAS asked authors to transfer copyright to the Academy. But instead of restricting author and reader rights
as a result of holding copyright, PNAS explicitly allowed authors and readers to use PNAS content for any educational use without having to request permission (1). Of course, papers authored solely by federal employees as part of their government employment are in the public domain
and copyright cannot be transferred.

Much like copyright transfer, the PNAS author license provides the journal with the legal protection it needs to use, distribute,
reuse, sublicense to third parties, and protect an article from unauthorized copying or alteration. PNAS will continue to
screen requests from commercial companies to use PNAS images and articles in their marketing materials or works for sale.
PNAS will also protect authors by taking action against improper use of material, for example, through plagiarism or duplicate
publication.

Our author license holds true to our core principle: anyone can freely use PNAS content for any educational use. In addition,
the license guarantees the following rights:

After publication in PNAS, authors can freely reuse their work for any educational use.

Authors can post the PDF of their article on their web page.

Authors can post and update the work on preprint servers such as arXiv.

Authors can deposit their manuscript in their funding body's archive or designated repository on acceptance for publication
by PNAS, and can request public access 6 months after print publication or immediately upon publication by PNAS if the authors
have paid the PNAS open access fee. PNAS automatically deposits the final version of all papers in PubMed Central.

PNAS analyzed in depth the merits of an author license versus a Creative Commons License. The Creative Commons License would
give the right of dissemination of the work to the world at large rather than to PNAS as the publisher. We decided that the
ambiguities of how a Creative Commons License defines noncommercial use and the possibility of unintended consequences for
both authors and the publisher from unrestricted redistribution of PNAS articles pose too great a risk to change to a Creative
Commons License at this time. Further, a Creative Commons License cannot be revoked and Creative Commons does not provide
any means to vindicate the author's rights if they have been violated (e.g., if someone uses the work for commercial exploitation,
Creative Commons plays no role in redressing the matter). We recognize and fully support the experiments of other publishers
with Creative Commons and hope that their experience will inform our future decisions.

The goal of PNAS and the Academy is not to restrict and control scientific research results or to seek financial gain from
publishing. Our goal is simply to disseminate the best scientific content as widely as possible. We believe that the PNAS
License to Publish strikes the right balance.